Two of the region’s biggest casino companies – Ameristar Casinos and Pinnacle Entertainment – poured another $500,000 into their bid to overturn Missouri’s casino loss-limits law in the second quarter, according to a filing this week with the Missouri Ethics Commission. (read the report here ^[1])

Each company donated $250,000 during the period to the Yes For Schools First Coalition , the group that’s pushing a measure on the November ballot that would end Missouri’s one-of-a-kind $500 loss limit, cap casino licenses and provide up to another $130 million in school funding. The only other donor in the quarter was the Missouri Gaming Association, which provided nearly $13,000 worth of in-kind donations.

All told, Ameristar has donated $1.21 million to the effort, and Pinnacle $1.19 million. Aside from the Gaming Association, they’ve been the only donors since Yes for Schools First was formed in December. Other casino groups, like Harrah’s Entertainment, have said they support the measure, but not donated money to it.

Both companies have a lot riding on the measure. They each have invested heavily in large casino-hotel properties in Missouri in recent years and say the card requirement and $500-per-two-hours cap on losses keeps high rollers out of Missouri casinos and prevents St. Louis from becoming a gaming tourist destination. Ameristar is also concerned about the launch of gaming in Kansas, near its property in Kansas City, Mo.

Also, last week, Yes for Schools First named a new spokesman: Scott Charton, formerly director of communications for the University of Missouri system.